Container having blown plastic liner and method and apparatus for forming same

ABSTRACT

This relates to a lined container, preferably of the fibre drum type, wherein the lining is extruded as an open ended tube and is initially adhered to the bottom or end wall of the container to seal the tube after which the tube is first inflated and blown across the end wall and is then blown within the container so as to conform to the interior configuration of the container body. The tube is formed by an extruder, and/or accumulator capable of intermittent extrusion with therebeing relative movement between a die associated with the extruder and the container during the extrusion of the tube, and after the entire interior of the container has been lined, there is associated with the die and the container a mold which upon further extrusion of the tube and the blowing of air within the tube the tube either may be caused to fold around the exterior free end portion of the container so as to form therearound or may be shaped to define a flange which is later draped around the container free end portion. In the case of a fibre drum, the formed or draped portion of the liner protects the metal reinforcing ring in the chime area against corrosion.

This is a division of application Ser. No. 794,993 filed May 9, 1977,now U.S. Pat. No. 4,127,430.

This invention relates in general to new and useful improvements inlined containers, and more particularly to a container having formedtherein a plastic lining which is applied in the form of an open tubeand is then simultaneously extruded and blown within the container so asto conform to the configuration of the container. The lining isparticularly adaptable for use in conjunction with fibre drums.

It is known to provide plastic liners for containers. Typical of priormodes of forming such liners is the formation of a bubble, positioningthe bubble within the container, and blow molding the same to theconfiguration of the container. Other modes include the preforming of alining on a core pin and then blow molding the preform in the container.Typical of such prior art are the U.S. Patents to Strong U.S. Pat. No.(2,898,972); Makowski No. (3,091,000); Meissner No. (3,169,086) andFuller No. (3,816,578).

In accordance with this invention, the extrusion from which the liner isformed is open-ended and does not require a tube or parison which hasbeen molded with a closed end or is pinched off.

In accordance with the invention, the leading or free edge of anopen-ended extrusion is adhered to the inside bottom surface of acontainer to form the seal necessary for blowing the extrusion undergaseous pressure. In order to effect the required seal, the bottomsurface must be especially prepared, as by coating, to effect or promoteadhesion, and insure liquid or vapor containment.

In accordance with the invention, it is also feasible to especiallyprepare, as by coating, the interior surface of the body of thecontainer to also effect or promote adhesion, and as required to meetspecifications.

In order to form a seal with a closure, it is desirable that theextrusion be folded over the upper free end of the container body; thismay be accomplished during the molding process or as a subsequentoperation. When the container is a fibre drum and the upper chime isdefined by a metal ring, it is desirable that the liner fold down overthe upper chime to protect the same against corrosion. In order toeffect this folding, there is provided a mold which is associated withthe upper portion of the container and the extrusion head after theinterior of the container has been lined and the extrusion is blowmolded within the mold either down around the upper chime of thecontainer or as a flange in the mold for later folding or draping aroundthe upper chime.

With the above, and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawings.

IN THE DRAWINGS

FIG. 1 is a schematic elevational view showing a conventional containerpositioned relative to a mold and an extrusion head preparatory to theapplication of a lining in accordance with this invention, the containerbeing partially broken away and shown in section.

FIG. 2 is an elevational view similar to FIG. 1 and shows the extrusionhead in telescoped relation with respect to the container and initiallyapplying a tubular extrusion to the bottom or end wall of the container,a latter blown bubble being shown in phantom lines.

FIG. 3 is an elevational view similar to FIG. 2 and shows the extrusionblown across the end wall and in the process of being blow molded to theinternal configuration of the container body.

FIG. 4 is a schematic sectional view through the container, the blowmold and the extrusion head with the lining substantially completelyapplied to the interior of the container.

FIG. 5 is a sectional view similar to FIG. 4 and shows the extrusionblow molded within the mold so as to fold and drape around the exteriorof the upper portion or chime of the container and with the extrusionsevered from the extrusion head.

FIG. 6 is a schematic sectional view of the upper portion of the linedcontainer with a waste portion of the extrusion severed therefrom.

FIG. 7 is an enlarged fragmentary vertical sectional view through anupper portion of the lined container and shows specifically the liningmolded about the exterior of the container.

FIG. 8 is a schematic elevational view similar to FIG. 1 of a modifiedmold arrangement for forming a liner flange to be later draped over thechime and illustrates that in lieu of the extrusion die moving down intothe fixed container, as shown in FIGS. 1-3, the extrusion head may befixed and the container and mold moved up into telescoped relation withrespect to the extrusion head.

FIG. 9 is a sectional view similar to FIG. 7 but shows the modifiedliner of FIG. 8 and its relation to the container both before and afterfolding thereof into its chime protecting position.

Referring now to the drawings in detail, it will be seen that there isillustrated in FIG. 1 a typical container which will be lined inaccordance with this invention with a lining formed of plasticsmaterial. The container is generally identified by the numeral 10 andthe illustrated container is a fibre drum. The container 10 includes abody 11 which is closed at its lower end by an end wall 12 which willnormally be the bottom wall of the container. The end wall 12 may beseparately formed or may be integral with the body 11. In the case of afibre drum, the lower portion of the body 11 will have a metalreinforcing ring 13 with this ring defining a lower chime of thecontainer.

It is also pointed out here that when the container is in the form of afibre drum, the upper end of the container will also be reinforced by ametal ring 14 which will define the upper chime of the container, themetal ring 14 serving both to reinforce the body 11 and to provide aproper seating surface for a closure (not shown) which is to be appliedto the container.

In FIG. 1 the container 10 is illustrated as having an internal coating15 which extends over the entire interior thereof. While it is preferredto apply the coating 15 to the entire interior of the container, it isto be understood that the coating could be restricted to a radiallyouter annular portion of the inner surface of the end wall 12. Thepurpose of the coating 15 is to assure adhesion of the plastics materialextrusion which is to be extruded by the extrusion heads.

In the illustrated form of the invention shown in FIGS. 1-5, thecontainer 10 is fixedly mounted on a suitable combined centering andsupporting device 16 and the extrusion head, generally identified by thenumeral 17, is mounted for vertical reciprocation between a positionelevated above the container, as shown in FIG. 1, to a position fullytelescoped within the container, as shown in FIG. 2. The extrusion headincludes a conventional die for extruding a tube and is suitablyconnected to a conventional extruder or accumulator for the intermittentextrusion of a tube of plastics material. An associated blow mold,generally identified by the numeral 18, is vertically fixed and isformed of identical sections 20 which may either be separable in ahorizontal plane, as shown in FIG. 4, or may be mounted for pivotalmovement in a clam-shell manner as shown in FIG. 8, to have selectivelyreceived within the blow mold 18 the upper portion of the container 10.

The die portion of the extrusion head 17 is provided with an annularextrusion orifice 21 which receives plastics material on a controlledand intermittent basis from the accumulator or extruder through apassage 22.

In order to effect the blow molding of an extruded plastics materialtube extruded by the extrusion head 21 within the container 10, theextrusion head 17 is also provided with a centrally located passage 23for a gas, normally air, under pressure. The passage 23 opens throughthe lower end of the extrusion head 17 within the confines of theorifice 21. At this time it is pointed out that the end wall 12preferably has a peripheral arrangement of apertures 19 and that thedevice 16 has a vacuum passage 29 formed therethrough for drawing avacuum within the container.

Referring now to FIG. 4 in particular, it will be seen that the blowmold 18 is of a configuration so as to clamp the exterior of thecontainer body 11 below the chime 14, as at 24. In the area of the chime14, the configuration of the blow mold 18 is such so as to leave a spacearound the chime 14 which will permit the forming of the extrudedplastics material down around the chime 14. This space is generallyidentified by the numeral 25. The space 25 is either suitably vented tothe atmosphere or connected to a vacuum source.

The upper portion of the blow mold 18 may be provided with a splitinsert 26 positioned for forming a seal at least with the underside ofthe extrusion head 17 and with portions of the split insert 26 havingactuating elements 27 to effect the movement of portions of the splitinsert relative to the extrusion head 17 to effect a shearing of theextrusion below the underside of the extrusion head 17. To this end,portions of the insert 26 are in the form of cutters 28. Other methodsof severing the parison, well known in the art of plastics materialprocessing, may be utilized eliminating the need for the inserts 26 andthe cutters 28.

OPERATION

As is shown in FIG. 1, the container 10 to be lined is properlypositioned with respect to the extrusion head 17 and the blow mold 18.The extrusion head 17 is then moved down into the container 10 until theunderside of the extrusion head 17 substantially engages the innersurface of the end wall 12. At this time extrusion of plastics materialin tubular form is initiated with the resultant extrusion, identified bythe numeral 30, being in pressure contact with the coating 15 on theinner surface of the end wall 12 so as to form a seal between theextrusion 30 and the container.

After the extrusion 30 has adhered to the end wall 12, gas (air) underpressure is directed through the passage 23 and the extrusion head 17 islifted slightly while more of the extrusion 30 is extruded. The netresult is that the extrusion 30 is blown as a bubble across the innersurface of the end wall 12 and into engagement with the interior surfaceof the body 11, as is shown in phantom lines in FIG. 3.

At the same time the vacuum drawn through the apertures 19 in the endwall assists in the shaping of the bubble to match the lower portion ofthe container interior. Then as the extrusion of the plastics materialcontinues together with the continued introduction of the gas underpressure, the extrusion head 17 is elevated with the extruded tubeconforming to the interior configuration of the body 11. This processcontinues until the extrusion head reaches a position near the top ofthe container 10 at which time the introduction of the gas underpressure and the extrusion of the plastics material may be temporarilydiscontinued.

The mold 18 is then closed, as shown in FIG. 4. After the mold 18 isclosed, the extrusion of the plastics material may continue togetherwith the introduction of further gas under pressure with the result thatthat portion of the extruded tube between the upper part of the interiorof the body 11 and the extrusion head 17 is forced downwardly andoutwardly in an open folded condition into the mold space 25 and aroundthe chime 14 to a position as shown in FIG. 5. At this time the liningof the container 10 is completed and the extrusion of the plasticsmaterial and the introduction of the gas under pressure is discontinued.Then the split portions of the inserts 26 are actuated so as to severthe extruded tube 30 from the plastics material within the extrusionhead 17 as is specifically shown in FIG. 5, or the extrusion isotherwise broken or separated from the die.

Following the completion of the liner, the mold 18 is vented and openedand the lined container is removed. Thereafter, the excess liningmaterial, identified by the numeral 31, is trimmed from the containerand is discarded as waste.

It will be readily apparent that the extrusion head 17 is now ready toform another lining within a next container and the mold 18 is open forthe reception of a next container.

In the embodiment of the invention illustrated in FIGS. 1 through 5, thecontainer 10 is mounted on a fixed support 16 and the extrusion head 17is vertically movable. On the other hand, it is to be understood thatthe extrusion head 17 may be vertically fixed and the supporting device16 is vertically movable. The mold 17 either may be fixed or moved withthe device 16. It is to be understood that the operation of suchapparatus will be the same, the only difference being that the containeris moved relative to the extrusion head as opposed to the extrusion headbeing movable relative to the container.

Referring now to FIG. 7, it will be seen that not only is the interiorof the container 10 fully lined with a lining 33, but also that liningis draped or molded over the exterior of the body 11 at the upper endthereof, as at 34, and covers the chime 14. The lining 33 exteriorly ofthe body 11 completely encases the desired part of the chime 14 so as toprotect the same against corrosion. In addition, the lining 33 overliesthe extreme end of the body 11 so as to form between the body 11 and aclosure (not shown) a seal.

It is to be understood that when the plastics material of the lining 33cools, it will have a tendency to conform exactly to the configurationof the interior of the container 10. However, if the entire interior ofthe container 10 is precoated with the coating 15, there will be anadherence of the lining 33 to the entire interior of the container 10.

Reference is now made to FIG. 10 wherein the extrusion head 17 is fixedand the supporting device 16 is mounted for vertical reciprocation bymeans of a lift device 36. Associated with the supporting device 16 is aframe 37 which may either be fixed so as to determine the lowermostposition of the supporting device 16 or which may be fixedly connectedto the supporting device 16 for movement therewith. The frame 37 has aplurality of upstanding supports 38 carried thereby in circumferentiallyspaced relation. Pivotally mounted as at 40 on the supports 38 aresections 41 of a split mold, generally identified by the numeral 42. Themold 42 has the sections 41 thereof opening in a clam-shell like manner,and each mold section 41 is provided with a lever 43 which, in turn, isconnected to an upper end of a piston rod 44 of a fluid motor 45. Thelower part of the fluid motor 45 is pivotally mounted on the frame 37 asat 46.

It is to be understood that there is a plurality of the fluid motors 45and that suitable conventional control means will be provided forsimultaneously actuating all the fluid motors 45 so as to simultaneouslyopen or close the mold 42.

The mold 42 is of a configuration so as to contact the chime 14 of thecontainer 10 about the exterior thereof in sealed relation as at 46. Themold 42 extends upwardly above the container 10 when the container 10 isseated therein so as to define a cavity 47. The cavity 47 isparticularly configurated to mold a flange 48 from the extrusion 30 asan upward and outward continuation of the lining 33 which is applied tothe container 10 in the manner set forth above with respect to theembodiment shown in FIGS. 1 through 5.

In order to assist the forming of the extrusion 30 to define the flange48, the cavity 47 is in communication with an exhaust passage 50 whichis connected to a suitable vacuum source.

The mold 42 has a conical extension 51 which extends up and istelescoped generally around the extrusion head 17. A gas tight seal isformed between the extension 51 and the extrusion head 17 by means of asealing strip 52.

At this time it is pointed out that extension 51 is provided withcooling coils 53 so as to facilitate the cooling of the extrusion 30when the extrusion 30 contacts the extension 51.

OPERATION

With the mold 42 open, the container 10 is moved upwardly until the endwall 12 thereof is contacting the extrusion 30 projecting from theunderside of the extrusion head 17, after which the lining 33 is appliedin the same manner applied and illustrated with respect to FIGS. 1-5except that the container is gradually moved downwardly during thelining thereof while extrusion head 17 remains fixed.

After the interior of the container 10 has been lined and the liner 33completely formed, extrusion of the plastics material continues togetherwith the maintaining of gaseous pressure within the extrusion 30. As aresult of the gaseous pressure internally of the extrusion 30 and thesuction applied in the suction passage 50, the extrusion 30 is drawninto the cavity 47 and the flange 48 is formed.

After the flange 48 has been formed, the extrusion above the flange israpidly cooled by its contact with the extension 51. Thus when the mold42 is opened, the extrusion 30 may be readily broken from the extrusionhead 17.

Referring now to FIG. 9, it will be seen that after the lined container10 has been removed from the mold 42, the extrusion 30 above the flange48 may be trimmed as at 54 with the extrusion 30 above the flange 48constituting waste 55 which is discarded and reused. Thereafter theflange 48 may be moved down around the upper part of the chime 14, asshown in phantom lines in FIG. 9, to protect the chime 14.

A comparison of the lined containers of FIGS. 7 and 9 will show that theresulting containers are substantially identical and that they differprimarily in whether the chime 14 is covered by plastics material whichis molded in place in the case of the container of FIG. 7 or which isfolded in place in the case of the container of FIG. 9.

Although only preferred embodiments of the invention have beenspecifically illustrated and described herein, it is to be understoodthat minor variations may be made in the apparatus and the methods ofutilizing the same without departing from the spirit and scope of theinvention, as defined by the appended claims.

I claim:
 1. A lined container, said lined container comprising acontainer including an end wall and a body, and a tubular lining, saidlining being bonded to said end wall about a preselected exposed area ofsaid end wall and extending across said end wall in stretched relationto said body, and said liner is in an expanded state above said end walland confirming to said body, said lining having a terminal annular endportion forming that part of said lining bonded to said container endwall about said preselected exposed area of said end wall.